From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id A6A32EE6B60 for ; Fri, 6 Feb 2026 21:11:54 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 1C7FE6B0098; Fri, 6 Feb 2026 16:11:54 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 1A9596B0099; Fri, 6 Feb 2026 16:11:54 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 0CCCE6B009B; Fri, 6 Feb 2026 16:11:54 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0012.hostedemail.com [216.40.44.12]) by kanga.kvack.org (Postfix) with ESMTP id F1A046B0098 for ; Fri, 6 Feb 2026 16:11:53 -0500 (EST) Received: from smtpin24.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay10.hostedemail.com (Postfix) with ESMTP id 8D1B9C182D for ; Fri, 6 Feb 2026 21:11:53 +0000 (UTC) X-FDA: 84415278906.24.F9EA4EF Received: from tor.source.kernel.org (tor.source.kernel.org [172.105.4.254]) by imf03.hostedemail.com (Postfix) with ESMTP id CD4F02000E for ; Fri, 6 Feb 2026 21:11:51 +0000 (UTC) Authentication-Results: imf03.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20201202 header.b=rhBEKlTs; spf=pass (imf03.hostedemail.com: domain of a.hindborg@kernel.org designates 172.105.4.254 as permitted sender) smtp.mailfrom=a.hindborg@kernel.org; dmarc=pass (policy=quarantine) header.from=kernel.org ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1770412311; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references:dkim-signature; bh=z+oMqxkPsm+SeIqFusF5Rf52C4m7bRaa8kb5aIAwKdU=; b=mIZilsGNRNlMxZJOh+PShEx136YqfbQ2T8DeUfsHMWo0K5B89EJ1+Oo4RxoIr6FRJFHSlV Ej1/tyE1vkvlopKH/Goog4mNpdedArmoTJjPttCQ/Q0RcfgdF9tJQMAFanaOFHWVYCXxWB g0PdYlYLp1Uf71lOrbQOa0WMUhhNF4c= ARC-Authentication-Results: i=1; imf03.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20201202 header.b=rhBEKlTs; spf=pass (imf03.hostedemail.com: domain of a.hindborg@kernel.org designates 172.105.4.254 as permitted sender) smtp.mailfrom=a.hindborg@kernel.org; dmarc=pass (policy=quarantine) header.from=kernel.org ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1770412311; a=rsa-sha256; cv=none; b=A24wyKGNWlbj6DAmTfutbJSs/L6ukPqe/4kiOqlJBSeqSDrEoQ25BWR1Fpvwl45oJqJ82g ryJmrg5i0erMQyI7+GxWcPnitwY0LgxAD0HkLHui0CKZzlA6RWYLqege4iUNUVM95ke8av SaF6riLmMd96tyRxbz+keCv/bCCXQhY= Received: from smtp.kernel.org (transwarp.subspace.kernel.org [100.75.92.58]) by tor.source.kernel.org (Postfix) with ESMTP id 49FC66014A; Fri, 6 Feb 2026 21:11:51 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 7702FC116C6; Fri, 6 Feb 2026 21:11:46 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1770412311; bh=2aA6TsP5TqOXxamqOrEM+ulf/tg/RPrxh0tZsqKQ8Qk=; h=From:Date:Subject:References:In-Reply-To:To:Cc:From; b=rhBEKlTsP62RAZDNXL4f6dTWS2K126rDj/IyPLRJ9fZW85Dhc0DG7jYthxD5w0iMs azv0CWMNz2OaTIjSVyKOPoZn6wHpdz8xmO5Tfm0uGZD+9Jkddc2azvX+jFgX0fJ1ap DMaQ5S2sebc4qRDD7FAfwPSIzixaAwphXH27Otk7KqchRQ5LGWaB92agMNmjW2EnRS xJXG7gzfAJdjKjVBiGs8Y9o2LgbJJyuEUN9BrA5aQY9U86ITgX7eTMKW4AfIqFLPEj +EK6tFG44dEQhQPqjuADRRkbk3zMWlPylpJsQrOGn0M9dSzxBA8BrRl0KKh/3o8ypb 1GBrfia7yZKPA== From: Andreas Hindborg Date: Fri, 06 Feb 2026 22:10:50 +0100 Subject: [PATCH v2 04/11] rust: xarray: add `XArrayState` MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Message-Id: <20260206-xarray-entry-send-v2-4-91c41673fd30@kernel.org> References: <20260206-xarray-entry-send-v2-0-91c41673fd30@kernel.org> In-Reply-To: <20260206-xarray-entry-send-v2-0-91c41673fd30@kernel.org> To: Tamir Duberstein , Miguel Ojeda , Alex Gaynor , Boqun Feng , Gary Guo , =?utf-8?q?Bj=C3=B6rn_Roy_Baron?= , Benno Lossin , Alice Ryhl , Trevor Gross , Danilo Krummrich , Lorenzo Stoakes , "Liam R. Howlett" , Vlastimil Babka , Andrew Morton , Christoph Lameter , David Rientjes , Roman Gushchin , Harry Yoo Cc: Daniel Gomez , rust-for-linux@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, Andreas Hindborg X-Mailer: b4 0.15-dev X-Developer-Signature: v=1; a=openpgp-sha256; l=3142; i=a.hindborg@kernel.org; h=from:subject:message-id; bh=2aA6TsP5TqOXxamqOrEM+ulf/tg/RPrxh0tZsqKQ8Qk=; b=owEBbQKS/ZANAwAKAeG4Gj55KGN3AcsmYgBphljkR6yFU74Qctxwfi+Hjmm+uCS+oAhwJVObd 03DdYekpUGJAjMEAAEKAB0WIQQSwflHVr98KhXWwBLhuBo+eShjdwUCaYZY5AAKCRDhuBo+eShj d7NJEACUN4BBgh5y31PGzMdcKchA+Aw6rT5w2nYg1DwlVMsSRzL7BZOOsYX0BrXCfJtsmRg91dM dLzCLv7Ar7zwcI80iJnrAG8sr+wg5wtepKUfDrTMbSyi6vJp4u+XfwqB4QS8iP36nQTIZ/ostYU 7xwkrXbTLtNr++3c+mo0tU1yUB9cFSYFHcfOR+KU4OI+OaV0agbPhkCur+W+yFgaE+yXzsJfuj+ /faayPfcGoTSrap9G3p78GaKxMKDiYTSVko8qtgbqoBvamPr7ZAokSztOfM/wLhu7lJD2CMAN5H f6FfU4KMs+gZXuHR3iyhDOVBXqpW60wdbvE4+etEFbY7FkY4SAUpXtLdgRb4YwW2M3lOOMUgFzz H5jeeUQhUFkib5dWWmahTU7iCe8BMDctvKP/BaK0M9y0g5FdyW2OVS75nG57V6rO/jsMUeM4b2Y ew/cD84r8n7LV1J5W/A5oiiPHXbSKQ+fHIJNSWxZ/zh+TrdED5Moo1ul2gBXJKJ2kguc1+Yx2+0 xVBGydN2BIb8KXmQbJr5gL1gSGnuuk0iJCKmDKYCW5baQhMbYwxTc4yXO4hNY548Xc+BepwqoH0 +Ujvysi8N7EqQPhESEe2AHlSXKCrLA/HEUHWrtdJlujsGqNVdWiTk+ZSXyZPETCnTzfxXLHjaT2 O0AcmXow/xyhDvA== X-Developer-Key: i=a.hindborg@kernel.org; a=openpgp; fpr=3108C10F46872E248D1FB221376EB100563EF7A7 X-Stat-Signature: odytk1jgsh4zcgktdop47oho6z6q45kn X-Rspam-User: X-Rspamd-Server: rspam08 X-Rspamd-Queue-Id: CD4F02000E X-HE-Tag: 1770412311-359616 X-HE-Meta: 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 zOSBKHmh UGb4rHNSNBTX7+fNmagwPP9ReGav5dQeM1pQNCa9I2N7u22NR5G8jHFat/+r92pWjU+nS3jbx4QDoc6f3b5adpZYIulQ8mQa4sgh9aJ2JiFQgo4Yx+BqebhED6NSYRip+3I2mZc5SAG0AKZjGFcEtWvwjeKvXoUpdKA7qkijvllWvpO6HY5N6le41EEzEggqNJV6bOMTWQPIc+nyHUvbUcGihWM/8YYuB3lGLXxHaoTaPPAbkTS0Hraexq8zN3aMmfG9YHqNbqOPC6Wrt5j1K8u/I9yxWI4UhpQjBOVITp0LZNyFR3WAYF6APZw== X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: Add `XArrayState` as internal state for XArray iteration and entry operations. This struct wraps the C `xa_state` structure and holds a reference to a `Guard` to ensure exclusive access to the XArray for the lifetime of the state object. The `XAS_RESTART` constant is also exposed through the bindings helper to properly initialize the `xa_node` field. The struct and its constructor are marked with `#[expect(dead_code)]` as there are no users yet. We will remove this annotation in a later patch. Signed-off-by: Andreas Hindborg --- rust/bindings/bindings_helper.h | 1 + rust/kernel/xarray.rs | 41 ++++++++++++++++++++++++++++++++++++++++- 2 files changed, 41 insertions(+), 1 deletion(-) diff --git a/rust/bindings/bindings_helper.h b/rust/bindings/bindings_helper.h index a067038b4b422..58605c32e8102 100644 --- a/rust/bindings/bindings_helper.h +++ b/rust/bindings/bindings_helper.h @@ -117,6 +117,7 @@ const xa_mark_t RUST_CONST_HELPER_XA_PRESENT = XA_PRESENT; const gfp_t RUST_CONST_HELPER_XA_FLAGS_ALLOC = XA_FLAGS_ALLOC; const gfp_t RUST_CONST_HELPER_XA_FLAGS_ALLOC1 = XA_FLAGS_ALLOC1; +const size_t RUST_CONST_HELPER_XAS_RESTART = (size_t)XAS_RESTART; const vm_flags_t RUST_CONST_HELPER_VM_MERGEABLE = VM_MERGEABLE; const vm_flags_t RUST_CONST_HELPER_VM_READ = VM_READ; diff --git a/rust/kernel/xarray.rs b/rust/kernel/xarray.rs index ede48b5e1dba3..d1246ec114898 100644 --- a/rust/kernel/xarray.rs +++ b/rust/kernel/xarray.rs @@ -8,7 +8,10 @@ iter, marker::PhantomData, pin::Pin, - ptr::NonNull, // + ptr::{ + null_mut, + NonNull, // + }, }; use kernel::{ alloc, @@ -319,6 +322,42 @@ pub fn store( } } +/// Internal state for XArray iteration and entry operations. +/// +/// # Invariants +/// +/// - `state` is always a valid `bindings::xa_state`. +#[expect(dead_code)] +pub(crate) struct XArrayState<'a, 'b, T: ForeignOwnable> { + /// Holds a reference to the lock guard to ensure the lock is not dropped + /// while `Self` is live. + _access: PhantomData<&'b Guard<'a, T>>, + state: bindings::xa_state, +} + +impl<'a, 'b, T: ForeignOwnable> XArrayState<'a, 'b, T> { + #[expect(dead_code)] + fn new(access: &'b Guard<'a, T>, index: usize) -> Self { + let ptr = access.xa.xa.get(); + // INVARIANT: We initialize `self.state` to a valid value below. + Self { + _access: PhantomData, + state: bindings::xa_state { + xa: ptr, + xa_index: index, + xa_shift: 0, + xa_sibs: 0, + xa_offset: 0, + xa_pad: 0, + xa_node: bindings::XAS_RESTART as *mut bindings::xa_node, + xa_alloc: null_mut(), + xa_update: None, + xa_lru: null_mut(), + }, + } + } +} + // SAFETY: `XArray` has no shared mutable state so it is `Send` iff `T` is `Send`. unsafe impl Send for XArray {} -- 2.51.2